If an XFail test throws a Skip exception, then treat it as a skip.
If an XFail test throws a Skip exception, then treat it as a skip.

Currently, XFail converts a "skip" result into a "pass".  But a "skip"
should remain a "skip".  (But since the pre-converted value is used to
choose what test result to output, this modification does not change
the printed output of any tests.)

* subversion/tests/cmdline/svntest/testcase.py (XFail.convert_result):
  Convert pass->fail, fail->pass, but leave skip->skip unchanged.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion